BACKGROUND OF THE INVENTION The number of services provided by mobile telephone operators has considerably increased in the past few years. The convergence of mobile communica- tion networks has enabled the creation of new value added services for mobile subscribers. A value added service of a mobile communication system may be e. g. the barring of different levels of an outgoing or in- coming call, versatile call diversion, call waiting service, conference call, advanced communications sys- tems, prepaid services, and separate billing service.

The arranging of charging and billing has been one challenging development area in the operation of operators. Especially one aim has been to offer to the clients of all operators the possibility of choice as regards the attributing of billing. For instance, the charging of specially priced calls and transac- tions of payment traffic conducted over the mobile station may be attributed to somewhere else than the account of the calling mobile station.

With the operator it is also possible to sign e. g. a 101 long-distance contract. In that case, the subscriber can make calls without a separate long- distance network identifier, and s (he) will be always able to know in what network the dialing takes place.

It is, however, not possible to utilize the tradi- tional 101 code in mobile communication systems.

The other call specification 151 is operator- specific, and does not therefore provide a sufficient additional value to the subscriber, since the service is bound to a specific operator. In both of the afore- mentioned systems, the subscriber makes a separate contract and uses in conjunction with the dialing the code required by the service.

A pocket subscription is one alternative in wishing to influence the differentiation of billing.

The holder of the pocket subscription does not neces- sarily need a subscription of his/her own, instead s (he) may call via a pocket subscriber number of his or her own that is dialed in the beginning of each call. The system works both in the national and inter- national calls, and the calling is independent of sys- tem and operator. The billing is attributed based on the aforementioned personal identification number of the pocket subscription.

The problem with the pocket subscription is the two-phase dialing. Series of numbers consisting of considerably many numbers are regarded cumbersome and long among the users.

A telecard service is one solution that has been designed specially for companies and their em- ployees. Telecard is specially the solution for people travelling on business that enables one to attribute the billing of calls and other telecommunication to the desired billing point. Also in this alternative the subscriber is confronted with the same problems as with the pocket subscription.

OBJECTIVE OF THE INVENTION The objective of the invention is to elimi- nate the drawbacks referred to above, or at least sig- nificantly to alleviate them. One specific objective of the invention is to disclose a new type of method

and system that allow one to differentiate the billing of specially priced calls from a normal telephone bill as well as make it possible to offer the specification service of the operator to the clients of several mo- bile communication systems.

BRIEF DESCRIPTION OF THE INVENTION The method in accordance with the invention relates to the arranging of billing in a telecommuni- cation system. In the invention, the billing of spe- cially priced services is differentiated from a normal telephone bill by using a separate identification character string, i. e. a prefix. By means of this identifier it is possible in the method of the inven- tion to attribute the invoice of the subscriber to the appropriate billing point. The telecommunication sys- tem comprises a telecommunication system, a terminal device, by which the subscriber is connected to the telecommunication network, and a mobile services switching center which is connected to the telecommu- nication network. In addition, the system comprises a home location register and a maintenance center which are connected to the mobile services switching center, as well as a service platform which is connected to the telecommunication network.

In the method of the invention, to the tele- communication network, the subscribers dialing is sent that comprises a prefix. The prefix is used to mean a character string beforehand determined and reserved that enables one to show whether the subscriber has got a special service and where one wishes to attrib- ute the billing to. The prefix is selected so that the call is automatically directed to a particular tele-

communication network. In conjunction with the call establishing also the identifier of the A subscriber is transmitted. In the method it is checked from the database of the home location register whether the subscriber has the special service in accordance with the aforementioned prefix activated, and certain in- formation of the location of the subscriber and the additional services selected by the subscriber are also checked.

After this, in the method of the invention, the billing method is checked from the database of the maintenance center of the telecommunication system by means of a database query for each user specifically.

The maintenance center, which is also called the cen- tralized center of maintenance of the mobile communi- cation network, is responsible for subscriber manage- ment, charging, as well as the handling of the error messages coming from the network. The maintenance cen- ter transfers the billing to a subscriber-specific billing point based on subscriber-specific defini- tions.

After the aforementioned measures, in the method of the invention, the subscribers dialing is directed, after number conversion, to the service platform.

In one embodiment of the invention, the bill is divided into two parts. The division is done so that in the first part there is generated the share of the subscription of the normal mobile telephone part, and in the second part there is generated the addi- tional charge part consisting of the special service that is billed via a separate billing system.

In one embodiment of the invention, in con- junction with the call establishment there is transmit- ted the A subscriber identifier, and in case the send- ing of the number has been barred, the call establish- ment is barred.

In addition, the invention relates to a sys- tem for arranging billing in a telecommunication sys- tem which comprises a telecommunication network, a terminal device, by which the subscriber is connected to telecommunication network, a mobile services switching center, which is connected to the aforemen- tioned telecommunication network, a home location reg- ister, which is connected to the aforementioned mobile services switching center, a maintenance center, which is connected to the aforementioned mobile services switching center, and a service platform which is con- nected to the aforementioned telecommunication net- work.

According to the invention, the telecommuni- cation system comprises a database checker which is used to check whether the special service defined for the user is activated. In the system in accordance with the invention, a database query component is used to check, for each user specifically, the billing method of the subscriber from the database of the maintenance center, and transferring means are used to transfer the bill, for each user specifically, to a subscriber-specific billing point in accordance with the definitions of the prefix.

The system also comprises a billing generator which enables one to divide the bill into two separate parts so that the first part comprises, according to the definitions, the subscribers share of the mobile communication connection setup, and the second part comprises the additional charge part, e. g. the cost resulting from the additional service, which is di- rected for billing via a separate system, e. g. to a credit card account.

As compared to prior art, the invention has the advantage that it enables one to differentiate the billing of specially priced calls from a normal tele- phone bill by means of a separate identifier, i. e.

prefix. The client may in this way select where and how s (he) wishes the billing to be implemented. In ad- dition, there is neither the two-phase dialing nor the long series of numbers appearing in the invention.

BRIEF DESCRIPTION OF THE DRAWINGS In the following section, the invention will be described by the aid of the attached examples of its embodiments with reference to the accompanying drawing, in which Fig. 1 schematically represents one embodi- ment of the system in accordance with the invention, and Fig. 2 represents one advantageous signaling diagram illustrating the function of the present in- vention.

DETAILED DESCRIPTION OF THE INVENTION The system as shown in Fig. 1 comprises a telecommunication network (MSN, Mobile Service Net- work), which in this example is a mobile communication network (PLMN, Public Land Mobile Network), e. g. a digital mobile network. The telecommunication network MSN comprises naturally also other network components than the ones important with regard to the function of the invention shown in Fig 1: the mobile services switching center (MSC, Mobile Service Switching Cen- ter) and home location register (HLR, Home Location Register). The system comprises also a terminal device (MS, Mobile Station), which is preferably a mobile station. The mobile stations MS are connected to the telecommunication network MSN e. g. via a radio inter- face. The system comprises also a separate billing system which comprises a maintenance center (OSS, Op- eration Sub-System). The separate billing system is

connected to the telecommunication network MSN. The system as shown in Fig. 1 comprises also a service platform (SP, Service Provider) which is connected to the telecommunication network MSN, as well as an in- telligent network (IN, Intelligent Network).

Further, the system as shown in Fig. 1 com- prises a database checker 1 located in the mobile services switching center MSC that is used to check from the home location register HLR whether the sub- scriber has the special service activated, a database query component 2 which is used to check the billing method of the subscriber from the database of the maintenance center OSS by means of a database query.

In addition, the maintenance center OSS of the system as shown in Fig. 1 comprises transferring means 3 which are used to transfer the billing, according to subscriber-specific definitions, to a subscriber- specific billing point.

The maintenance center OSS comprises also a billing generator 4 which is used to divide the bill into two parts so that the billing generator 4 gener- ates in the first part the share of the subscription of the call establishment, and in the second part the additional charge part consisting of the special serv- ice that is directed to be billed via a separate sys- tem.

In Fig. 1 there is shown also the intelligent network IN. The intelligent network IN is needed in order that the mobile subscriber could be offered new services. The subscriber is attached to the services of the intelligent network IN by a number conversion of the mobile services switching center (MSC). The signaling is consistent with the common channel sig- naling (SS7, Signaling System number 7), and the com- munication e. g. between a GSM network and the intelli- gent network takes place in accordance with the INAP protocol. The INAP protocol utilizes the service ele-

ments of applications (ASE, Application Service Ele- ments), and together with the part responsible for the transactions (TCAP, Transaction Capability Application Part) enables the access of the mobile subscriber to the services (Mobile Application Entity) of the intel- ligent network IN. The intelligent network IN as shown in Fig. 1 may comprise the following components: the signal transfer point (STP, Signaling Transfer Point), service switching point (SSP, Service Switching Point), service control point (SCP, Service Control Point).

The intelligent network IN allows the mobile subscriber to access certain services. The subscriber can e. g. have his or her car washed in a car wash automate. The subscribers dialing is identified in the mobile services switching center (MSC) as being a num- ber of the intelligent network IN, and it is directed, after the number conversion, to the intelligent net- work IN. The responsibilities of the intelligent net- work include activating the service desired by the subscriber. In this kind of situation the subscriber may wish to differentiate the billing of the specially priced services from a normal telephone bill.

Fig. 2 represents, by way of example, one advantageous signaling diagram illustrating the func- tion of the present invention. According to Fig. 2, the subscribers dialing, which contains the A sub- scriber identifier (A-id), is sent from the mobile station MS to the telecommunication network MSN, arrow 21. The dialing may comprise an identifier in accor- dance with at least two different character strings that is used to indicate, for each subscriber specifi- cally, how and where the subscriber is billed and to which telecommunication network MSN one wishes the call to be automatically directed. The telecommunica- tion network MSN identifies the subscribers dialing, process 22. In the identification process 22, the da-

tabase checker 1 of the mobile services switching cen- ter MSC is used to check, based on the MAP protocol, from the home location register HLR whether the sub- scriber is having a special service. After this, the database query component 2 of the mobile services switching center MSC is used to check, by means of a database query, the subscribers billing method from the database of the separate billing system, process 23. The database query is e. g. a database query con- sistent with SQL (SQL, Structured Query Language). The SQL is a common database query language using which it is possible to make entries and queries e. g. to the databases of the network components of the mobile com- munication systems. In the subscriber-specific process of generating the bill 24 of the separate billing sys- tem, the following facts are checked: whether the whole bill is debited via the separate billing system or whether the bill is divided into two parts. If the bill is divided into two parts, then in the first part there will be the subscribers share of the call estab- lishment, and in the second part there will be the share consisting of the special service that is deb- ited via the separate billing system. This second part may be attributed, for each subscriber specifically, e. g. to the billing point of a credit card.

After this, the subscribers dialing is di- rected without the prefix, based on the C number re- ceived from the number conversion, via the intelligent network IN, to the service platform SP, arrow 25.

The invention is not restricted merely to ex- amples of its embodiments, instead many variations are possible within the scope of the inventive idea.